Cerebral palsy (CP) is regarded as the most common cause of severe motor disability in children (1); approximately 10,000 new cases are diagnosed each year in the United States (2). Although motor impairment is the primary defining feature of CP, other disabilities such as mental retardation, seizure disorder, and learning disabilities often co-occur (3-5). Research suggests that 60% of children with CP have communication problems (6); however, the exact nature of these problems has never been comprehensively examined. Existing research has emphasized differentiation of speech features based on the nature of the gross motor movement disorder (7-12) (i.e. athetoid vs. spastic). Language and cognitive variables have been controlled in these studies by including only those with normal abilities. Because learning disabilities and mental retardation frequently accompany CP, a true account of communication must include simultaneous quantification of speech, language, and cognitive abilities. There have been significant advances in the study of gross motor development (13-17), fine motor development (18-21), and brain imaging findings in children with CP (5, 6, 22-25). However, the lack of data regarding communication and its development has prohibited a thorough understanding of the constellations of and inter-relations among deficits that accompany CP. Using a multidimensional theoretical perspective, this project will quantify longitudinal development of speech, language, and cognition at 6 month intervals over a period of 4 years. A cohort of 80 children with CP and 17 typically developing children, who are 2-4 years of age at the onset of the study, will be followed. Hypotheses are: 1.) there are identifiable and longitudinally stable communication-based subgroups within the population of children who have CP; and 2.) these subgroups are loosely related to gross motor, fine motor, and brain imaging findings for these same children. Specific aims that target these hypotheses are to: a.) establish subgroups of children with CP on the basis of cross sectional communication (speech, language, and cognition) profiles (Aim 1); b.) quantify developmental changes in speech, language, and cognitive abilities and determine the stability of communication subgroup membership over time in young children with CP (Aim 2); c.) identify the extent to which gross and fine motor classifications are associated with communication subgroup membership (Aim 3); and d.) characterize structural neuro-anatomical involvement and determine how patterns of neuropathology are associated with communication subgroup membership (Aim 4). Results will inform an initial theory of communication development in children with CP that emphasizes the inter-relations among speech, language, and cognition. The longitudinal methodology will enable development of growth curves for individual children and for the putative communication subgroups. Results will have direct clinical implications for communication intervention and will also advance the broader theoretical understanding of CP, where classification of speech and language problems has been identified as a high priority (3, 26). PUBLIC HEALTH RELEVANCE: Cerebral palsy (CP) is the most common cause of severe motor disability in children; approximately 800,000 Americans are living with CP. Most children with CP have communication problems, but very little is known about the specific nature of these problems. This research will examine communication development over time in children with CP and will identify communication-based subgroups of children who have similar kinds of problems. Results will lead to a better understanding of communication prognoses and ultimately may lead to interventions that enhance communication outcomes in children with CP.